The invention relates to a power transformer suitable for use in switching power supplies intended for use with very high speed integrated circuit (VHSIC) applications, wherein the drive is by pulse width modulation at a frequency of 50,000 Hertz or more.
It is desirable to have a compact, low-loss manufacturable power transformer able to operate over wide temperature ranges with no change in characteristics. As size gets smaller, efficiency must be very high (greater than 98 percent) since the loss (as heat) must be dissipated from a small volume. Effective heat transfer methods must be used to sustain continuous operation. A high input-to-output turns ratio, which is related to the input voltage (115 VAC or 220 VAC) to output voltage (approximately 2 VDC) ratio, requires unique winding materials and techniques to maintain a high quality transformer having minimum copper loss and low leakage inductance (less than 1 .mu.H).